The experimental use of light in combination with Albert Einstein's Quantum nature of light, based on the work of Philippe Lenard on the wavelength theory (1905) won him his only Nobel Prize in 1921.
The research of Thomas Young 102 years prior to these two men showed that light is made of waves. Waves spread out whereas light particles are contained in one place. Einstein demonstrated this using the photoelectric effect, that light is made of particles, or photons, and that the photons of high-frequency light have more energy than the photons of low-frequency light.
In Einstein's theory, each photon of a given color, i.e. green, has a certain amount of energy. Reducing the intensity of a beam of green light only reduces the number of photons in the beam. Each remaining photon still has the same amount of energy as any other photon of green light.
These researchers and others delved into the organic properties of light. Color became the major influence to begin utilizing the color combinations that changed moods, promoted relaxation, altered negative behavior and perception through penetration of the correct colored light wavelengths absorbed by the photoreceptors of the eye, and the responsiveness of the frontal and temporal lobes to this new therapeutic combination. Neil Bohr, Shealy, Babbitt and Dr. Ott have all researched various organic effects of colors.
What are still needed are non-invasive methods for treating autism spectral disorders.